compact sha make digest an unicode string

common/python/nomadcore/compact_sha.py

@@ -7,11 +7,11 @@ class CompactHash(object):
         self._proto = proto
 
     def b64digest(self):
-        return base64.b64encode(self.digest(), "-_")[:-2]
+        return base64.b64encode(self.digest(), b"-_")[:-2].decode("ascii")
 
     def b32digest(self):
         res = base64.b32encode(self.digest())
-        return res[:res.index('=')]
+        return res[:res.index('=')].decode("ascii")
 
     def update(self, data):
         if type(data) == type(u""):